Revert r180578, r180591, and r180604 from 1410 branch.

media/base/audio_renderer.h

Index: media/base/audio_renderer.h
===================================================================
--- media/base/audio_renderer.h	(revision 182591)
+++ media/base/audio_renderer.h	(working copy)
@@ -18,7 +18,8 @@
 class AudioDecoder;
 class DemuxerStream;
 
-class MEDIA_EXPORT AudioRenderer {
+class MEDIA_EXPORT AudioRenderer
+    : public base::RefCountedThreadSafe<AudioRenderer> {
  public:
   typedef std::list<scoped_refptr<AudioDecoder> > AudioDecoderList;
 
@@ -26,9 +27,6 @@
   // Second parameter is the maximum time value that the clock cannot exceed.
   typedef base::Callback<void(base::TimeDelta, base::TimeDelta)> TimeCB;
 
-  AudioRenderer();
-  virtual ~AudioRenderer();
-
   // Initialize a AudioRenderer with the given AudioDecoder, executing the
   // |init_cb| upon completion.
   //
@@ -92,6 +90,12 @@
   // decoded audio buffer.
   virtual void ResumeAfterUnderflow(bool buffer_more_audio) = 0;
 
+ protected:
+  friend class base::RefCountedThreadSafe<AudioRenderer>;
+
+  AudioRenderer();
+  virtual ~AudioRenderer();
+
  private:
   DISALLOW_COPY_AND_ASSIGN(AudioRenderer);
 };